Influence of gold nanoparticles size for photocatalytic NO oxidation in low loading Au/TiO <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="d1e1158" altimg="si56.svg"> <mml:msub> <mml:mrow/> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> </mml:math> catalysts
Manuel Luna, Álvaro Cruceira, Ana Díaz, José M. Gatica, María J. Mosquera
Abstract
Gold nanoparticles (AuNPs) supported on TiO2 are one of the most investigated photocatalysts, however, the positive effect of AuNPs size reduction on Au/TiO 2 activity is clear for conventional catalysis, but this relationship not strictly happens in photocatalysis. The present work investigates how small changes in the lower size range of AuNPs can affect the Au/TiO2 photoactivity in order to maximize the performance of photocatalysts with low metal loadings (<1 wt%). Precipitation–deposition methods and a speciation-controlled incipient wetness impregnation (ScIWI) method have been employed for preparing Au/TiO 2 photocatalysts that exhibited a NOx elimination capacity significantly higher than pristine TiO2. Comparing the photocatalysts, ScIWI method achieved the highest gold dispersion and Au–TiO2 contact perimeter providing the most active photocatalysts, confirming the positive effect of AuNPs size reduction in the average sizes around 2 nm. In addition, on the basis of the results obtained, it has been proposed that the adsorption of nitrogen oxides species on gold has a relevant role on the NO photooxidation process.